What could be a possible reason for the front disc tightening after the bike has been ridden for approximately twenty minutes. This has got me puzzled as its not tight when the bike has been standing but is noticeable to the point its harder to pedal after three or four miles. Any suggestions would be great.

Kindest regards

Are you sure your not just getting tired, does it only happen when you go up hill?

😀

Are the pads contacting the disc in any form?, the slightest rub may not present a problem upon spinning the front wheel but continued rubbing of the pad may lead to heat expansion of the calliper fluid and thus bind the brake on – just an idea

Are the pistons returning properly? I assume that after time standing they move back enough but upon several uses they don’t . If this is the case you may need to lube the pistons: take the pads out and go through the same motions you would for replacing the pads to return the pistons fully. Then gently apply the brake to get the pistons out, use a cotton wool bud dipped in lube, do this several times. Be careful not to over extend the pistons out of their housing. Sorry if you’ve tried this already.

What brakes are they, Avid im guessing?

What he said….

Had a guy onrq tour with this.

It sounds like the pistons are getting stuck.

Most likely heat build up. Brake pistons don’t move each time you brake; the flexibility of the seals allows the movement needed for braking. As the pads wear the pistons creep through the seals to take up the slack but if you’ve ever tried to remove them you’ll know that they cannot move when you brake then retract by slipping through the seals.

For reference the brakes in question are Clarks SX, thanks for all the help so far guys its most helpful.